Bump webpacker from 3.5.5 to 4.0.2 (#10277)

Bumps [webpacker](https://github.com/rails/webpacker) from 3.5.5 to 4.0.2.
- [Release notes](https://github.com/rails/webpacker/releases)
- [Changelog](https://github.com/rails/webpacker/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rails/webpacker/compare/v3.5.5...v4.0.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>
Co-authored-by: Yamagishi Kazutoshi <ykzts@desire.sh>

1 files changed, 0 insertions, 21 deletions

diff --git a/config/webpack/loaders/babel_external.js b/config/webpack/loaders/babel_external.js
deleted file mode 100644
index 39e74ed90..000000000
--- a/config/webpack/loaders/babel_external.js
+++ /dev/null
@@ -1,21 +0,0 @@
-const { resolve } = require('path');
-
-const env = process.env.NODE_ENV || 'development';
-
-if (env === 'development') {
-  module.exports = {};
-} else {
-  // babel options to apply only to external libraries, e.g. remove-prop-types
-  module.exports = {
-    test: /\.js$/,
-    include: /node_modules/,
-    loader: 'babel-loader',
-    options: {
-      babelrc: false,
-      plugins: [
-        'transform-react-remove-prop-types',
-      ],
-      cacheDirectory: env === 'development' ? false : resolve(__dirname, '..', '..', '..', 'tmp', 'cache', 'babel-loader-external'),
-    },
-  };
-}